Multi-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, at least four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes actuatable in combinations of two to establish a plurality of forward gear ratios and one reverse gear ratio.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/594,112 filed Feb. 2, 2012. The disclosure of the above applicationis incorporated herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, at least four planetary gear sets and a plurality oftorque transmitting devices

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

Further features, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a stick diagram of the embodiment of the ten speedtransmission shown in FIG. 1;

FIG. 3 is a lever diagram of another embodiment of a ten speedtransmission according to the present invention;

FIG. 4 is a lever diagram of another embodiment of a ten speedtransmission according to the present invention;

FIG. 5 is a lever diagram of another embodiment of a ten speedtransmission according to the present invention;

FIG. 6 is a lever diagram of another embodiment of a ten speedtransmission according to the present invention; and

FIG. 7 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmissions illustrated inFIGS. 1-6.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of themulti-speed automatic transmissions of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. A second component or element of a firstplanetary gear set is permanently coupled to a third component orelement of the third planetary gear set. A third component or element ofthe first planetary gear set is permanently coupled a second componentor element of the second planetary gear set. A third component orelement of the second planetary gear set is permanently coupled to asecond component or element of the third planetary gear set and a thirdcomponent or element of the fourth planetary gear set. A first componentor element of the third planetary gear set is permanently coupled to asecond component or element of the fourth planetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14, a second planetary gear set 16, a third planetarygear set 18 and a fourth planetary gear set 20 and an output shaft ormember 22. In the lever diagram of FIG. 1, the first planetary gear set14 has three nodes: a first node 14A, a second node 14B and a third node14C. The second planetary gear set 16 has three nodes: a first node 16A,a second node 16B and a third node 16C. The third planetary gear set 18has three nodes: a first node 18A, a second node 18B and a third node18C. The fourth planetary gear set 20 has three nodes: a first node 20A,a second node 20B and a third node 20C.

The input member 12 is continuously coupled to the first node 16A of thesecond planetary gear set 16. The output member 22 is coupled to thesecond node 14B of the first planetary gear set 14 and the third node18C of the third planetary gear set 18. The second node 14B of the firstplanetary gear set 14 is coupled to the third node 18C of the thirdplanetary gear set 18. The third node 14C of the first planetary gearset 14 is coupled to the second node 16B of the second planetary gearset 16. The third node 16C of the second planetary gear set 16 iscoupled to the second node 18B of the third planetary gear set 18. Thefirst node 18A of the third planetary gear set 18 is coupled to secondnode 20B of the fourth planetary gear set 20. The second node 18B of thethird planetary gear set 18 is coupled to the third node 20C of thefourth planetary gear set 20.

A first clutch 26 selectively connects the input member or shaft 12 andthe first node 16A of the second planetary gear set 16 with the firstnode 18A of the third planetary gear set 18 and the second node 20B ofthe fourth planetary gear set 20. A second clutch 28 selectivelyconnects the input member or shaft 12 and the first node 16A of thesecond planetary gear set 16 with the third node 16C of the secondplanetary gear set 16, the second node 18B of the third planetary gearset 18 and the third node 20C of the fourth planetary gear set 20. Athird clutch 30 selectively connects the second node 20B of the fourthplanetary gear set 20 and the first node 18A of the third planetary gearset 18 with the third node 18C of the third planetary gear set 18, thesecond node 14B of the first planetary gear set 14 and the output member22. A first brake 32 selectively connects the first node 20A of thefourth planetary gear set 20 with a stationary member or transmissionhousing 50. A second brake 34 selectively connects the first node 18A ofthe third planetary gear set 18 and the second node 20B of the fourthplanetary gear set 20 with the stationary member or transmission housing50. A third brake 36 selectively connects the third node 16C of thesecond planetary gear set 16, the second node 18B of the third planetarygear set 18 and the third node 20C of the fourth planetary gear set 20with the stationary member or transmission housing 50. A fourth brake 38selectively connects the first node 14A of the first planetary gear set14 with the stationary member of transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofan embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, aring gear member 14C and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14A is connected for common rotation with a first shaft orinterconnecting member 42. The ring gear member 14C is connected forcommon rotation with a second shaft or interconnecting member 44. Theplanet carrier member 14B is connected for common rotation with theoutput shaft or member 22. The planet gears 14D are each configured tointermesh with both the sun gear member 14A and the ring gear member14C.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16A is connected for common rotation with the input shaft ormember 12. The ring gear member 16C is connected for common rotationwith a third shaft or interconnecting member 46. The planet carriermember 16B is connected for common rotation with the second shaft orinterconnecting member 44. The planet gears 16D are each configured tointermesh with both the sun gear member 16A and the ring gear member16C.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18C and a planet gear carrier member 18B that rotatably supportsa set of planet gears 18D (only one of which is shown). The sun gearmember 18A is connected for common rotation with a fourth shaft orinterconnecting member 48 and a fifth shaft or interconnecting member52. The ring gear member 18C is connected for common rotation with theoutput shaft or member 22. The planet carrier member 18B is connectedfor common rotation with the third shaft or interconnecting member 46and with a sixth shaft or interconnecting member 54. The planet gears18D are each configured to intermesh with both the sun gear member 18Aand the ring gear member 18C.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The sun gearmember 20A is connected for common rotation with a seventh shaft orinterconnecting member 56. The ring gear member 20C is connected forcommon rotation with an eighth shaft or interconnecting member 58 andwith the sixth shaft or interconnecting member 54. The planet carriermember 20B is connected for common rotation with the fifth shaft orinterconnecting member 52 and with a ninth shaft or interconnectingmember 60. The planet gears 20D are each configured to intermesh withboth the sun gear member 20A and the ring gear member 20C.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 26, 28, 30 and brakes 32,34, 36 and 38 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the input shaft or member 12 with the fourth shaft orinterconnecting member 48. The second clutch 28 is selectivelyengageable to connect the input shaft or member 12 with the third shaftor interconnecting member 46. The third clutch 30 is selectivelyengageable to connect the output shaft or member 22 with the fifth shaftor interconnecting member 52 and the ninth shaft or interconnectingmember 60. The first brake 32 is selectively engageable to connect theseventh shaft or interconnecting member 56 with the stationary elementor the transmission housing 50 in order to restrict the member 56 fromrotating relative to the transmission housing 50. The second brake 34 isselectively engageable to connect the ninth shaft or interconnectingmember 60 with the stationary element or the transmission housing 50 inorder to restrict the member 60 from rotating relative to thetransmission housing 50. The third brake 36 is selectively engageable toconnect the eighth shaft or interconnecting member 58 with thestationary element or the transmission housing 50 in order to restrictthe member 58 from rotating relative to the transmission housing 50. Thefourth brake 38 is selectively engageable to connect the first shaft orinterconnecting member 42 with the stationary element or thetransmission housing 50 in order to restrict the member 42 from rotatingrelative to the transmission housing 50.

Turning to FIG. 3, another embodiment of a ten speed transmission 100 isillustrated in a lever diagram format. The transmission 100 is similarto the transmission 10 illustrated in FIGS. 1 and 2, however, the thirdclutch 30 has an alternate connection. The third clutch 30 selectivelyconnects the second node 20B of the fourth planetary gear set 20 and thefirst node 18A of the third planetary gear set 18 with the second node18B of the third planetary gear set 18, the third node 16C of the secondplanetary gear set 16 and the third node 20C of the fourth planetarygear set 20.

Turning to FIG. 4, another embodiment of a ten speed transmission 200 isillustrated in a lever diagram format. The transmission 200 is similarto the transmission 10 illustrated in FIGS. 1 and 2, however, the thirdclutch 30 has an alternate connection. The third clutch 30 selectivelyconnects the first node 20A of the fourth planetary gear set 20 with thesecond node 20B of the fourth planetary gear set 20 and the first node18A of the third planetary gear set 18.

Turning to FIG. 5, another embodiment of a ten speed transmission 300 isillustrated in a lever diagram format. The transmission 300 is similarto the transmission 10 illustrated in FIGS. 1 and 2, however, the thirdclutch 30 has an alternate connection. The third clutch 30 selectivelyconnects the first node 20A of the fourth planetary gear set 20 with thethird node 20C of the fourth planetary gear set 20, the second node 18Bof the third planetary gear set 18, and the third node 16C of the secondplanetary gear set 16.

Turning to FIG. 6, another embodiment of a ten speed transmission 400 isillustrated in a lever diagram format. The transmission 400 is similarto the transmission 10 illustrated in FIGS. 1 and 2, however, the thirdclutch 30 has an alternate connection. The third clutch 30 selectivelyconnects the first node 20A of the fourth planetary gear set 20 with thethird node 18C of the third planetary gear set 18, the second node 14Bof the first planetary gear set 14, and the output member 22.

Referring now to FIGS. 1-7, the operation of the ten speed transmissions10, 100, 200, 300, and 400 will be described. It will be appreciatedthat transmissions 10, 100, 200, 300, and 400 are capable oftransmitting torque from the input shaft or member 12 to the outputshaft or member 22 in at least ten forward speed or torque ratios and atleast one reverse speed or torque ratio. Each forward and reverse speedor torque ratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, first brake 32, second brake 34, third brake 36 andfourth brake 38), as will be explained below. FIG. 7 is a truth tablepresenting the various combinations of torque-transmitting mechanismsthat are activated or engaged to achieve the various gear states. An “X”in the box means that the particular clutch or brake is engaged toachieve the desired gear state. An “O” represents that the particulartorque transmitting device (i.e. a brake or clutch) is on or active, butnot carrying torque. Actual numerical gear ratios of the various gearstates are also presented although it should be appreciated that thesenumerical values are exemplary only and that they may be adjusted oversignificant ranges to accommodate various applications and operationalcriteria of the transmissions 10, 100, 200, 300, and 400. Of course,other gear ratios are achievable depending on the gear diameter, gearteeth count and gear configuration selected.

For example to establish a reverse gear, first clutch 26 and third brake36 are engaged or activated. The first clutch 26 connects the inputshaft or member 12 with the fourth shaft or interconnecting member 48.The third brake 36 connects the eighth shaft or interconnecting member58 with the stationary element or the transmission housing 50 in orderto restrict the member 58 from rotating relative to the transmissionhousing 50. Likewise, the ten forward ratios are achieved throughdifferent combinations of clutch and brake engagement, as shown in FIG.7.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmissions 10, 100, 200, 300, and 400assumes, first of all, that all the clutches not specifically referencedin a given gear state are inactive or disengaged and, second of all,that during gear shifts, i.e., changes of gear state, between at leastadjacent gear states, a clutch engaged or activated in both gear stateswill remain engaged or activated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

The invention claimed is:
 1. A transmission comprising: an input member;an output member; first, second, third and fourth planetary gear setseach having first, second and third members; a first interconnectingmember continuously interconnecting the second member of the firstplanetary gear set with the third member of the third planetary gearset; a second interconnecting member continuously interconnecting thethird member of the first planetary gear set with the second member ofthe second planetary gear set; a third interconnecting membercontinuously interconnecting the third member of the second planetarygear set with the second member of the third planetary gear set and withthe third member of the fourth planetary gear set; a fourthinterconnecting member continuously interconnecting the first member ofthe third planetary gear set with the second member of the fourthplanetary gear set; and seven torque transmitting mechanisms eachselectively engageable to interconnect at least one of the first,second, and third members with at least one other of the first, second,third members and a stationary member, and wherein the seven torquetransmitting mechanisms are selectively engageable in combinations of atleast two to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member.2. The transmission of claim 1 wherein a first of the seven torquetransmitting mechanisms is selectively engageable to interconnect theinput member and the first member of the second planetary gear set withthe first member of the third planetary gear set and the second memberof the fourth planetary gear set.
 3. The transmission of claim 1 whereina second of the seven torque transmitting mechanisms is selectivelyengageable to interconnect the input member and the first member of thesecond planetary gear set with the third member of the second planetarygear set, the second member of the third planetary gear set, and thethird member of the fourth planetary gear set.
 4. The transmission ofclaim 1 wherein a third of the seven torque transmitting mechanisms isselectively engageable to interconnect the first member of the thirdplanetary gear set and the second member of the fourth planetary gearset with the second member of the first planetary gear set, the thirdmember of the third planetary gear set, and the output member.
 5. Thetransmission of claim 1 wherein a fourth of the seven torquetransmitting mechanisms is selectively engageable to interconnect thefirst member of the fourth planetary gear set with the stationarymember.
 6. The transmission of claim 1 wherein a fifth of the seventorque transmitting mechanisms is selectively engageable to interconnectthe first member of the third planetary gear set and the second memberof the fourth planetary gear set with the stationary member.
 7. Thetransmission of claim 1 wherein a sixth of the seven torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe second planetary gear set, the second member of the third planetarygear set, and the third member of the fourth planetary gear set with thestationary member.
 8. The transmission of claim 1 wherein a seventh ofthe seven torque transmitting mechanisms is selectively engageable tointerconnect the first member of the first planetary gear set with thestationary member.
 9. The transmission of claim 1 wherein the inputmember is continuously connected for common rotation with the firstmember of the second planetary gear set.
 10. The transmission of claim 1wherein the output member is continuously connected for common rotationwith the second member of the first planetary gear set and with thethird member of the third planetary gear set.
 11. The transmission ofclaim 1 wherein the first members are sun gear member, the secondmembers are carrier members, and the third members are ring gearmembers.
 12. A transmission comprising: an input member; an outputmember; first, second, third and fourth planetary gear sets each havingfirst, second and third members; a first interconnecting membercontinuously interconnecting the second member of the first planetarygear set with the third member of the third planetary gear set; a secondinterconnecting member continuously interconnecting the third member ofthe first planetary gear set with the second member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the third member of the second planetary gear set withthe second member of the third planetary gear set and with the thirdmember of the fourth planetary gear set; a fourth interconnecting membercontinuously interconnecting the first member of the third planetarygear set with the second member of the fourth planetary gear set; afirst torque transmitting mechanism selectively engageable tointerconnect the input member and the first member of the secondplanetary gear set with the first member of the third planetary gear setand the second member of the fourth planetary gear set; a second torquetransmitting mechanism selectively engageable to interconnect the inputmember and the first member of the second planetary gear set with thethird member of the second planetary gear set, the second member of thethird planetary gear set, and the third member of the fourth planetarygear set; a third torque transmitting mechanism selectively engageableto interconnect the first member of the third planetary gear set and thesecond member of the fourth planetary gear set with the second member ofthe first planetary gear set, the third member of the third planetarygear set, and the output member; a fourth torque transmitting mechanismselectively engageable to interconnect the first member of the fourthplanetary gear set with the stationary member; a fifth torquetransmitting mechanism selectively engageable to interconnect the firstmember of the third planetary gear set and the second member of thefourth planetary gear set with the stationary member; a sixth torquetransmitting mechanism selectively engageable to interconnect the thirdmember of the second planetary gear set, the second member of the thirdplanetary gear set, and the third member of the fourth planetary gearset with the stationary member; a seventh torque transmitting mechanismselectively engageable to interconnect the first member of the firstplanetary gear set with the stationary member, and wherein the seventorque transmitting mechanisms are selectively engageable incombinations of at least two to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 13. The transmission of claim 12 wherein the inputmember is continuously connected for common rotation with the firstmember of the second planetary gear set.
 14. The transmission of claim12 wherein the output member is continuously connected for commonrotation with the second member of the first planetary gear set and withthe third member of the third planetary gear set.
 15. The transmissionof claim 12 wherein the first members are sun gear member, the secondmembers are carrier members, and the third members are ring gearmembers.
 16. A transmission comprising: an input member; an outputmember; first, second, third and fourth planetary gear sets each havinga sun gear member, a carrier member, and a ring gear member; a firstinterconnecting member continuously interconnecting the carrier memberof the first planetary gear set with the ring gear member of the thirdplanetary gear set; a second interconnecting member continuouslyinterconnecting the ring gear member of the first planetary gear setwith the carrier member of the second planetary gear set; a thirdinterconnecting member continuously interconnecting the ring gear memberof the second planetary gear set with the carrier member of the thirdplanetary gear set and with the ring gear member of the fourth planetarygear set; a fourth interconnecting member continuously interconnectingthe sun gear member of the third planetary gear set with the carriermember of the fourth planetary gear set; a first torque transmittingmechanism selectively engageable to interconnect the input member andthe sun gear member of the second planetary gear set with the sun gearmember of the third planetary gear set and the carrier member of thefourth planetary gear set; a second torque transmitting mechanismselectively engageable to interconnect the input member and the sun gearmember of the second planetary gear set with the ring gear member of thesecond planetary gear set, the carrier member of the third planetarygear set, and the ring gear member of the fourth planetary gear set; athird torque transmitting mechanism selectively engageable tointerconnect the sun gear member of the third planetary gear set and thecarrier member of the fourth planetary gear set with the carrier memberof the first planetary gear set, the ring gear member of the thirdplanetary gear set, and the output member; a fourth torque transmittingmechanism selectively engageable to interconnect the sun gear member ofthe fourth planetary gear set with the stationary member; a fifth torquetransmitting mechanism selectively engageable to interconnect the sungear member of the third planetary gear set and the carrier member ofthe fourth planetary gear set with the stationary member; a sixth torquetransmitting mechanism selectively engageable to interconnect the ringgear member of the second planetary gear set, the carrier member of thethird planetary gear set, and the ring gear member of the fourthplanetary gear set with the stationary member; a seventh torquetransmitting mechanism selectively engageable to interconnect the sungear member of the first planetary gear set with the stationary member,and wherein the seven torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.
 17. The transmission of claim 16wherein the input member is continuously connected for common rotationwith the sun gear member of the second planetary gear set.
 18. Thetransmission of claim 17 wherein the output member is continuouslyconnected for common rotation with the carrier member of the firstplanetary gear set and with the ring gear member of the third planetarygear set.